In wiper blades, the support element is intended to assure the most uniform possible distribution, over the entire field swept by the wiper blade, of the contact pressure of the wiper blade on the window, which pressure originates in the wiper arm. Because of an appropriate curvature of the unstressed support element xe2x80x94that is, when the wiper blade is not resting on the windowxe2x80x94the ends of the wiper strip, which in wiper blade operation are placed fully against the window, are urged by the then-tensed support element toward the window, even if the radii of curvature of spherically curved vehicle windows differ in each wiper blade position. Accordingly, the curvature of the wiper blade has to be somewhat greater than the greatest curvature measured in the field to be swept of the window to be wiped. The support element thus replaces the complicated support bracket construction with two spring rails, disposed in the wiper strip, as they are used in conventional wiper blades (German patent disclosure DE-OS 15 05 357.)
The invention is based on a wiper blade as generically defined by the preamble to claim 1. In a known wiper blade of this type (DE 196 27 115.0 A1) must be provided with a separate wind repelling strip, or spoiler, if the tendencies of the wiper blade to lift away from the window at relatively high travel speeds are to be averted. If this spoiler is to be disposed on the side of the support element remote from the window, difficulties can arise in replacing the used wiper strip, at least whenever this replacement is done by the end user of the wiper blade. That is, this process requires not only the replacement of the wiper strip but further installation work with regard to the spoiler.
In the wiper blade according to the invention, as defined by the characteristics of the body of claim 1, it is possible for this spoiler to be formed integrally and economically onto the wiper strip; the recesses make an inconspicuous, problem-free placement of the retainers possible. Special installation steps for the spoiler are dispensed with. Because of the adaptation of the outer profile of the retainer to the profile of the spoiler, the spoiler remains operative over its full length, because no gaps that impair the contact pressure distribution remain. Even edges that occur at the recesses and can lead to an undesired reinforcement of the wind noise occurring in the wiper blade are covered by the retainers.
For attaching the wiper blade to a driven wiper arm, the retainer is disposed in the longitudinal middle portion of the support element and is provided with means for attaching a wiper arm of this kind.
To avoid the risk of injury from the sharp-edged ends of the longitudinal rails when a person is manipulating the wiper blade, at least one retainer is disposed on one end of the support element and is provided with means for covering the end edges of the longitudinal rails.
In the case of especially long wiper blades, it has proved advantageous if a further retainer is disposed between the retainer disposed in the longitudinal center portion and the retainer disposed on the end of the support element, because this prevents a portion of a longitudinal rail from snapping out of its longitudinal groove, with the attendant loss of wiping quality.
Simple securing of the longitudinal rails in their longitudinal grooves is attained if each retainer, with at least one kt, clasps a respective one of the two longitudinal rails on its longitudinal edges.
To lend the retainer the stability required during operation of the wiper blade, the groovelike recess, in the spoiler is filled by a body of the retainer, which body has the extension.
To achieve an attractive appearance of the wiper blade, in terms of the length of the wiper blade, the length of the retainer is adapted to the length of the groovelike recess.
Since in the course of time the material comprising the wiper strip and the spoiler integrally joined to it ages, which is associated with a certain shrinkage, air gaps can arise between the retainers and the end faces, toward them, of the spoiler portions; these gaps can lead to the disadvantages already mentioned in terms of appearance and noise reinforcement. In a refinement of the invention, this can be hindered by providing that the retainer is provided with a wall, which extends longitudinally of the wiper blade and which covers a peripheral region of the spoiler, adjacent to the recess, on the back wall on the spoiler, remote from the leading-edge face.
Another possible way of overcoming the above disadvantages is obtained if the body of the retainer, on its face end toward the recess wall of the spoiler, is provided with a recess, into which the spoiler plunges with a respective end piece.
Expediently, the retainer is made from a plastic.
Further advantageous refinements and features of the invention are disclosed in the ensuing description of exemplary embodiments, shown in the associated drawing.